Tissue sections of brains from patients with multiple sclerosis (MS) and from control
individuals were immunostained with MHC class II and glial or vascular endothelial cell
antibodies and analyzed by confocal microscopy. MHC class II was abundant in and around
actively demyelinating MS lesions and was detected on microglia, phagocytic macrophages,
and perivascular macrophages. Astrocytes and vascular endothelial cells were MHC class II-
negative. Changes in the size and shape of MHC class II-positive cells associated with MS …